How vigilant are you when it comes to the TDS of your RODI water?

How vigilant are you when it comes to the TDS of your RODI water?

  • It is VERY important to me

    Votes: 378 62.9%
  • It is somewhat important to me

    Votes: 177 29.5%
  • It is NOT important to me

    Votes: 35 5.8%
  • Other (please explain in thread)

    Votes: 11 1.8%

  • Total voters
    601

revhtree

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TDS = Total Dissolved Solids

Happy Monday and let's talk TDS! For me if feels like I am always chasing zero when it comes to the TDS of my RODI water for water changes and especially top off water. But how concerned should I be and if zero isn't critical what is an acceptable number? Let's talk about it today!

"Sometimes tap water contains potential contaminants (such as phosphates or trace metals) which might be safe for human consumption, but could have detrimental effects on your aquarium life. For this reason many hobbyists use reverse osmosis deionized (RODI) filters on their source water. RODI filters can be a very effective way of removing contaminants from your aquarium. Although using a RODI system is simple, many factors can limit their effectiveness. Range and accuracy are critical aspects for instruments used for measurements in pure water applications. In order to measure the effectiveness of your RODI filter, many units have built in total dissolved solids or TDS meters." Excerpt via an awesome article by Marine Depot.

1. How vigilant are you when it comes to RODI TDS and keeping your numbers around zero?

2. What is the maximum TDS number you are comfortable with?



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Topreefer92

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I believe it is the foundation of providing that great water quality so I budget high for the best system I can get and replacing those filters. 0 tds in that water container is all I want. Especially where I live the water tds is horrendous (600-700) so we eat through filters quicker.
 

Bugeater281

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I’m probably less picky than a lot of people. I tend to hover between 1-4 tds. But I also don’t have a built in tds meter. And that 1-4 tds could easily come from the container I put the water into to test. You leave 0 tds water in a brand new food grade bucket with no lid. You’ll be up to 15 tds in 24 hours. This is the reason the 1-4 doesn’t bother me. If a bucket just sitting there can gain that much tds in 24 hours. There no way I can accurately test tds. That tds could Be coming from my mixing barrel, some dust in the air, the actual rodi lines.

I have a suspicion that some bacteria may be left in the water after filtration, and going from 250tds to pure rodi probably kills some bacteria off. Leading to a bit of tds in the water.
 

dbowman5

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i have the BRS 4 stage 75 gpd; the resin was 3/4 blue when i was given it in May of '19. It was 1 ppm TDS using the HM digital TDS-3.
Since I add 'Prime' to new water the TDS comes up to about 30 ppm before mixing with salt.
Recently the result changed to 2 , still ok in my book.
As i finished my last batch it was 3 and the resin was all brown. I changed all the media, since i had it on hand since June, now I have 0 ppm out of the RODI unit.
 

piranhaman00

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I use only 0 TDS water. I use 5 DI stages to ensure nothing gets through, the fifth stage is a safety for the first 4 :)

I go through resin fast though, I get about 150 gallons per canister.
 

andrewkw

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My source water quality is very good so if I get to 1 TDS after DI I will swap it out. Only need to change every year though. The problem with that is it can be harder to remember to check all the time. That being said it usually gets to the point where I change the DI even if it's still showing 0, just to be safe. If I was burning through DI like some people I would be less willing to do this.

The one thing I am not crazy about doing is letting the first little bit of water which may have some TDS creep drip out. I let that go into the barrel as well since I have it setup so that my RO/DI goes right into a 55g barrel that has a lid on it.
 

Ippyroy

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My RODI gives me water at 0 TDS, both in and out. My TDS is about 20 - 25 from the tap. But those 20 - 25 are radon, copper, and other nasties that would kill my tank in very short order. I feel that the number is a total mystery unless you do the leg work and find out what they are. The simplest thing to do is call whomever supplies your water and get the most recent in detail water report.
 

K7BMG

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To my wallets detriment I am a RO/DI crazy person.
I am on a well and took my water in for testing.
I had better quality water than I thought. My concern was Silicates and Arsenic.
Clearly I have no chlorines, but a lot of sediment.

Anyway I want 0 TDS in my product water. After everything I have read about water quality being the first step in the key to a healthy successful Reef Tank.
I have two three probe TDS meters on my system for redundancy. I have paired the probes on the source line, after the RO filter, and of course the product water.

I also make sure the probe pins are properly aligned to avoid any misreading's.
My readings on the source water are the only ones that disagree.
Unit A will read a consistent 12 lower than Unit B.
Unit A reads a TDS at 183 where unit B will read 195.
The second pair after the RO reads identically and will bounce between 7-8.
The source has always been at 0.

I attest this to the way I run my DI canisters.
I use color changing Cation, Anion, and Mixed bed in that order.
I use three canisters per resin and do the shuffle method.
When canister A is exhausted its removed, canister B moves to spot A, canister C moves to spot B, and the newly filled canister goes to C.
 

Paulie069

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What’s TDS I don’t make salt water I use all ocean water 100%,,, does it have TDS ???? I’m
 

Auquanut

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1. How vigilant are you when it comes to RODI TDS and keeping your numbers around zero?
I guess I would say fairly diligent. I have an AWC system and a large ATO reservoir, so I will sometimes make up to 75 gallons of water at a time. If the TDS out goes from 0 to 1 while I'm making water, I'll just keep on going and change DI resin (and filters/RO membrane if needed) before the next batch.

2. What is the maximum TDS number you are comfortable with?
I've had TDS go up to 5 while making water, and I'm not too worried about it. I've noticed that once TDS starts climbing, it does so pretty quickly. If it went higher than that, I might stop the process and change out the resin. I always have replacements standing by.
 

sfin52

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After a year di resin is still blue. I guess I'm ok. Theres a tds meter?

I have one that also test salinity and ph. I got it from a water treatment plant for Christmas last year. Ive used it to test ph.
 
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